Nancy,
The first thing I would suggest, and bear with me, it'll sound kinda nutty... is to actually EAT your Flex & Exercise Points. Yes, really
With your level of activity, and the "long time" you have been on WW, I would guess that your body has slowed down its metabolism. I've heard members (in my meetings in the past) say that eating all "extra" accumulated Points actually kicked their body back into fat-burning mode. I suspect you might be burning too many calories exercising for the amounts of Points you are eating... putting you into starvation mode.
I would think you can get below 152-155... you may just have to feed those hardworking muscles of yours a bit more!
Good luck! Tell us how it goes for you!